How much does Ph matter

[DeepWater]

I have started to fill a new fish tank with some nice communal fish (Danios, Tetras, Cory catfish, Cherry Barbs, Culi loaches).  While checking the nitrate/amonia/nitrite levels I learned my water ph is about 8.6.  The water from tap and well have the same ph level.  Do I need to drop the ph down?  Or just keep on keeping on?

[Craziiininja]

Keep it stable. Dont use any ph down or any products like that. You could add some driftwood if you dont already have some that will lower your ph a little bit. Its always better to keep your ph stable rather than trying to chase the perfect ph. My ph is 8.2 and i keep all the common community fish like you have listed with no problems. Just keep it stable and the fish will adapt to it and be just fine. 

[GardenStateGoldfish]

keep it stable like Crazi said, 

However, it is an important to keep an eye on it because if you notice your PH dropping over time its time for a water change or to add crushed coral, because it means the buffering capacity in your water has run out, and the ph will continue to drop to unstable levels. So I would say its important to watch, but the number itself is just important to keep at whatever your water change PH is. 

[AdamTill]

It’s good to know what the reality of your water is.

At high pH, it’s SUPER important to make sure you never expose your fish to high levels of ammonia and nitrite. It’s extremely toxic at high pH.

Likewise, some fish probably won’t do as well. Cardinals raised in hard water have been necropsied and found to have calcium deposits in their kidneys. It would logical to think that affects their health, but lots of people keep them at high pH with no issues.

The worst thing you can do, as said, is fight the pH using chemicals. That’s pointless, and will harm the fish. Some people choose to cut the water with RO to have a lower (stable) pH, but that’s a lot of work.

Far better to pick fish that will do well. Goldfish, cichlids etc will be super happy.

[FrozenFins]

as everyone else mentioned in this thread, keep it stable. Fluncuations of ph can cause stress.

I keep my aquariums at 7.5ph

[Marc]

I wouldn't worry about it with those fish or fish you buy locally. If you happen to buy fish online then be sure to find out what PH they are kept at, Going from PH 7.0 to 8.6 could shock the fish if not properly acclimated.

[Steph’s Fish and Plants]

In my 3 (well now 2 bc I just tore one down in leu of a saltwater tank) freshwater tanks I haven’t tested the pH since I set them back up. I don’t even own a pH test kit at this point. What I Do test is the Kh. Kh is your buffer capacity and what keeps the pH stable, so if I have enough of that, I know my pH isn’t going anywhere. pH is only important in certain scenarios, such as highly sensitive shrimp, African cichlids, and tank crashes. Now the first two are still variable but it’s more important to be in their desired ranges than community fish and other types of cichlids. In the case of tank crashes, it’s my understanding that when the pH drops below a certain point, somewhere around 6.2 or 6.3 or something, ammonia gets converted to the non toxic ammonium, which isn’t broken down by the bacterial colonies in the tank, so it builds up and up and up until we change the water and the pH rises back up. Then, all that ammonium that’s been building up instantly becomes ammonia and shocks the system and is often times higher than what the bacteria, which have been dying off without a food source, can handle. This is a tank crash and often leads to large die offs from the combination of pH changes and high levels of toxic ammonia. A pH in the lower 8s is really of no concern however, unless you’re trying to keep extremely fancy shrimp like caridina and other similar, highly sensitive species. 

[Casper]

My pH from the tap is around 8.2, my local fish store told me I could mix distilled water in with my tap water (making sure I still use a dechlorinater) and that would help me maintain a lower more stable pH for the fish as well as making sure that the beneficial minerals and stuff in tap water are still getting added to the tank since those are removed during the distillation process. My pH with that method is around 7.6 to 7.8.

[DeepWater]

Thanks